The invention relates to an axial piston machine of the kind having an oblique-axle construction with a tiltable cylinder drum and a drive-connected drive pulley stationarily supported in a casing, pistons movable in cylinder bores of the drum being articulated to the drive pulley via ball-and-socket joints and with a control mirror member with control ports (reniform) which face the outlets of the cylinder bores, a cylindrical backside of the mirror member facing away from the control mirror being supported on a suitably shaped guide surface of the casing, and the control mirror member being tiltable by an adjusting device which tilts the cylinder drum, in order to adjust the stroke of the engine, and the bearing surface being provided with orifices connected with suction and pressure ducts for the pressure medium, which orifices are connected with the control ports via conduits penetrating through the control mirror member.
These types of axial piston machines have become known, for example from the published German Patent Application No. 1,017,468. They are particularly suitable for small-scale closed drives and excell by a noiseless and low-vibration running even at high pressures and speeds.
The cylinder drum is rotatably mounted on the control mirror member and is supported by the latter, the back side of the mirror member facing away from the control mirror on the mirror member being supported on the cylindrical slideway in the pump housing. This per se advantageous basic concept, however, causes difficulties for the admission and evacuation of the conveying medium, since the admission and evacuation of the conveying medium to the cylinder bores must proceed from the suction or pressure ducts in the pump housing through the control mirror member, and this passage of the medium must occur during all positions of tilt of the cylinder drum and of the control mirror member.
For these reasons, the angle of tilt of all hitherto known machines is limited in that, on the pressure-feeding side, the slots or orifices for passing the pressure medium through the control mirror member and the orifice of the pressure duct in the guide surface in the pump housing must overlap over the entire area of tilt of the control mirror member, and the pressure duct in the pump housing must at all times be covered up and sealed by the control mirror member against the interior of the pump housing. Further, the size of the apertures in the mirror member may only be such that the compression forces acting on the mirror member and the surrounding sealing surfaces will not lift the mirror member off its slideway. The angle of tilt still possible due to these limitations is not sufficient for meaningfully utilizing such a machine also in reverse drive. In other words, it is impossible with pumps of this species to tilt the mirror member with cylinder drum from a middle position with zero stroke for the pistons within the cylinder drum in two directions, so that, when the direction of rotation is maintained, the direction of feed of the pressure medium is reversed at the drive shaft, that is, a transposition of pressure and suction duct takes place.